/**
 * Copyright (C) 2001-2017 by RapidMiner and the contributors
 * 
 * Complete list of developers available at our web site:
 * 
 * http://rapidminer.com
 * 
 * This program is free software: you can redistribute it and/or modify it under the terms of the
 * GNU Affero General Public License as published by the Free Software Foundation, either version 3
 * of the License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
 * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Affero General Public License for more details.
 * 
 * You should have received a copy of the GNU Affero General Public License along with this program.
 * If not, see http://www.gnu.org/licenses/.
*/
package com.rapidminer.gui.tools.syntax;

/*
 * SyntaxUtilities.java - Utility functions used by syntax colorizing Copyright (C) 1999 Slava
 * Pestov
 * 
 * You may use and modify this package for any purpose. Redistribution is permitted, in both source
 * and binary form, provided that this notice remains intact in all source distributions of this
 * package.
 */

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;

import javax.swing.text.Segment;
import javax.swing.text.TabExpander;
import javax.swing.text.Utilities;


/**
 * Class with several utility functions used by jEdit's syntax colorizing subsystem.
 * 
 * @author Slava Pestov, Ingo Mierswa
 */
public class SyntaxUtilities {

	/**
	 * Checks if a subregion of a <code>Segment</code> is equal to a string.
	 * 
	 * @param ignoreCase
	 *            True if case should be ignored, false otherwise
	 * @param text
	 *            The segment
	 * @param offset
	 *            The offset into the segment
	 * @param match
	 *            The string to match
	 */
	public static boolean regionMatches(boolean ignoreCase, Segment text, int offset, String match) {
		int length = offset + match.length();
		char[] textArray = text.array;
		if (length > text.offset + text.count) {
			return false;
		}
		for (int i = offset, j = 0; i < length; i++, j++) {
			char c1 = textArray[i];
			char c2 = match.charAt(j);
			if (ignoreCase) {
				c1 = Character.toUpperCase(c1);
				c2 = Character.toUpperCase(c2);
			}
			if (c1 != c2) {
				return false;
			}
		}
		return true;
	}

	/**
	 * Checks if a subregion of a <code>Segment</code> is equal to a character array.
	 * 
	 * @param ignoreCase
	 *            True if case should be ignored, false otherwise
	 * @param text
	 *            The segment
	 * @param offset
	 *            The offset into the segment
	 * @param match
	 *            The character array to match
	 */
	public static boolean regionMatches(boolean ignoreCase, Segment text, int offset, char[] match) {
		int length = offset + match.length;
		char[] textArray = text.array;
		if (length > text.offset + text.count) {
			return false;
		}
		for (int i = offset, j = 0; i < length; i++, j++) {
			char c1 = textArray[i];
			char c2 = match[j];
			if (ignoreCase) {
				c1 = Character.toUpperCase(c1);
				c2 = Character.toUpperCase(c2);
			}
			if (c1 != c2) {
				return false;
			}
		}
		return true;
	}

	/**
	 * Returns the default style table. This can be passed to the <code>setStyles()</code> method of
	 * <code>SyntaxDocument</code> to use the default syntax styles.
	 */
	public static SyntaxStyle[] getDefaultSyntaxStyles() {
		SyntaxStyle[] styles = new SyntaxStyle[Token.ID_COUNT];

		styles[Token.COMMENT1] = new SyntaxStyle(Color.black, true, false);
		styles[Token.COMMENT2] = new SyntaxStyle(new Color(0x990033), true, false);
		styles[Token.KEYWORD1] = new SyntaxStyle(Color.black, false, true);
		styles[Token.KEYWORD2] = new SyntaxStyle(Color.magenta, false, false);
		styles[Token.KEYWORD3] = new SyntaxStyle(new Color(0x009600), false, false);
		styles[Token.LITERAL1] = new SyntaxStyle(new Color(0x650099), false, false);
		styles[Token.LITERAL2] = new SyntaxStyle(new Color(0x650099), false, true);
		styles[Token.LABEL] = new SyntaxStyle(new Color(0x990033), false, true);
		styles[Token.OPERATOR] = new SyntaxStyle(Color.black, false, true);
		styles[Token.INVALID] = new SyntaxStyle(Color.red, false, true);

		return styles;
	}

	/**
	 * Paints the specified line onto the graphics context. Note that this method munges the offset
	 * and count values of the segment.
	 * 
	 * @param line
	 *            The line segment
	 * @param tokens
	 *            The token list for the line
	 * @param styles
	 *            The syntax style list
	 * @param expander
	 *            The tab expander used to determine tab stops. May be null
	 * @param gfx
	 *            The graphics context
	 * @param x
	 *            The x co-ordinate
	 * @param y
	 *            The y co-ordinate
	 * @return The x co-ordinate, plus the width of the painted string
	 */
	public static int paintSyntaxLine(Segment line, Token tokens, SyntaxStyle[] styles, TabExpander expander, Graphics gfx,
			int x, int y) {
		Font defaultFont = gfx.getFont();
		Color defaultColor = gfx.getColor();

		for (;;) {
			byte id = tokens.id;
			if (id == Token.END) {
				break;
			}

			int length = tokens.length;
			if (id == Token.NULL) {
				if (!defaultColor.equals(gfx.getColor())) {
					gfx.setColor(defaultColor);
				}
				if (!defaultFont.equals(gfx.getFont())) {
					gfx.setFont(defaultFont);
				}
			} else {
				styles[id].setGraphicsFlags(gfx, defaultFont);
			}

			line.count = length;
			x = Utilities.drawTabbedText(line, x, y, gfx, expander, 0);
			line.offset += length;

			tokens = tokens.next;
		}

		return x;
	}

	// private members
	private SyntaxUtilities() {}
}
